Humbling oneself to empirical understanding is the way left, at least from the right-center at which the Western political community is stuck (the way left of left-center is trickier and proposed in the second paragraph). Sticking one's head in the ground and believing what you want to believe rather than what is evident or logical (see: drug testing welfare recipients, climate change, supply side economics for examples) is the way right. This rightward position naturally has to do with some, most often misplaced, sense of power preservation, whether from an economic, ethnic, national, racial, or sexual standpoint, as is evident in aggressive positions on globalism, wealth distribution, and social empowerment. However, it's expressed perversely in rightist thought due to an aversion to even pragmatic self interest, which is why you see so many poor persons voting against their own interests, convincing themselves that plutocrats and the ultra-rich are somehow working in their favor.
The way left is education and deconstruction of class logic that undermines democratic-capitalist pragmatism. Once pragmatism is wholly embraced, and all of society reaps its benefits (this basically just implies basic political solidarity towards the end of achieving some demand-side capitalist state, social democracy, etc. that creates a more efficient distribution of resources in the marketplace) the moral codes of leftism will be free to express themselves, or not.
As far as strategy goes, posing leftward movement in reactionary and ultra-capitalist terms I would hope would prove more successful than alternative approaches. For instance, I always try to convince persons of the virtues of single payer healthcare on capitalist bases (lower per capita costs, increased economic mobility, reduced transactional costs) instead of pulling the compassion or "it's a human right" arguments.
